BirdAnalyst
Species · BCR 22 · BBS 2026 Release · 1966–2025

Vesper Sparrow In Eastern Tallgrass Prairie

All regionsEastern Tallgrass PrairieGrassland birds

Vesper Sparrow in Eastern Tallgrass Prairie has fallen sharply: down 73% on the route-weighted index since 1968.

-73%Since 1968TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
215Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Vesper Sparrow has fallen sharply in Eastern Tallgrass Prairie: down 73% on the route-weighted index since 1968.

Vesper Sparrow In Eastern Tallgrass Prairie Population Forecast

If the recent trend holds, Vesper Sparrow in Eastern Tallgrass Prairie is projected to rise about 11% by 2030 — from 2.5 in 2025 to a central estimate of 2.7 (95% range 0.09–5.4). A 5-year backtest shows a typical error of ±62.1%, with 100% of held-out values landing inside the 95% band.

+11%Change by 2030TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
2.7Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.09–5.495% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±62.1%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Vesper Sparrow in Eastern Tallgrass Prairie is projected to rise about 11% by 2030 — from 2.5 in 2025 to a central estimate of 2.7 (95% range 0.09–5.4). A 5-year backtest shows a typical error of ±62.1%, with 100% of held-out values landing inside the 95% band.19662030
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20263.00.335.6
20272.90.275.5
20282.80.215.5
20292.80.155.4
20302.70.095.4

Routes In Eastern Tallgrass Prairie

Routes recording Vesper Sparrow in Eastern Tallgrass Prairie.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Cedar ValleyIOWA461997
PrairieburgIOWA272000
BudaILLINOIS242023
PontiacILLINOIS212025
FairlandILLINOIS212025
SextonINDIANA182016
KentonOHIO182013
FairburyILLINOIS162025
AustinMINNESOTA162023
AtkinsonILLINOIS152024
Le RoyILLINOIS152025
BloomvilleOHIO152025
W LafayetteINDIANA142025
StreatorILLINOIS132025
MonticelloILLINOIS132025
ShannonILLINOIS132025
Grape CreekILLINOIS132025
EssexILLINOIS122025
Ash CreekMINNESOTA122025
ThurstonNEBRASKA122025
SheffieldILLINOIS112024
MinonkILLINOIS112024
HarristownILLINOIS112025
HolcombILLINOIS102025
Troy GroveILLINOIS102025

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.